pure pumice?

[MikeDom]

This is pumice which I bought from a UK nursery many years ago, mesh graded at 7 - 13 mm. No rubbish in here, but it was probably more expensive than the eBay stuff. They also sold 3 - 8 mm but I’ve used all that up so can't show you.

[Chris L]

This is the 1mm to 4mm stuff from the eBay seller quoted above.

Thankfully there doesn't seem to be too much dust, but I am not convinced that planting stuff in this "as is" is any better than the other stuff, which being so big would be a mealy bug haven.

I have done the dunking test and most of it (both cases) has sunk to the bottom. I will re-try that test once I know I've got some that is completely dry.

Before I do any major transplanting I think a few experiments on how long it stays wet for are in order. The smaller stuff might be OK if mixed with my normal granite grit.
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[MatDz]

[...]

Before I do any major transplanting I think a few experiments on how long it stays wet for are in order. The smaller stuff might be OK if mixed with my normal granite grit.

I've actually done something along that, based on the weight of water absorbed and then lost across 2 days. Don't have the numbers with me now and am away for a few days, but happy to share afterwards.

I've compared 1-4 pumice, 4-10 pumice, ECP absorbent/Tesco cat litter, Sanicat pink and my current mix with about 20% JI2/40% potting grit/40% Sanicat.

[Terry S.]

Doing measurements, you will get some sort of comparative data. But how do you know what you want, i.e. which is actually best for plant growth?

[MatDz]

Doing measurements, you will get some sort of comparative data. But how do you know what you want, i.e. which is actually best for plant growth?

A total try and error, on my side at least. I'm trying to understand what holds more water and for longer to be able to adjust the potting mix accordingly, for which I think the results were pretty predictable, e.g. larger particles dry off quicker, but I think they hold more water "inside". I'll share the numbers after the weekend!

Edit: My ultimate goal is assigning all plants into maybe 3 mixes of JI2, potting grit and Sanicat in ratios of (just an example): 20/40/40, 20/20/60 and 20/60/20, depending on the plant's water needs. I really hope this will simplify watering.

[Deltron]

Most of my caudiciforms are potted in Bob Potter's pumice with no issues.

This winter, they'll all be in the house with the central heating in an airy, light spot. On that basis, should I be misting them time to time to stop roots rotting? I have a mix of pachypodium, adenia, cyphostemma, and various pachycauls.

Does anyone have similar experience they can share please?

[Deltron]

^anyone please?

Experience of over-wintering in the house? To mist/sip or not?

[Chris L]

^anyone please?

Experience of over-wintering in the house? To mist/sip or not?

Possibly better asking question in a thread of its own?

[chris25]

I'm just picking this thread up again to get myself up to date on what's currently available. I've tried various options in the past but without the opportunity to "shop", as it were, I need to look again at mail order.

Firstly, I can't seem to find the Ikea product (Vaxer) any more; does anyone know if this is likely to be available in the future. It's an expensive option but I've found that it's very good for small plants and seed-raising.

Secondly, I have a bag of the moler clay as used to mop up spills in garages, etc. and I like it, especially for the price, but it's a bit fine for larger plants. I understand that Sanicat is similar but has a larger particle size. Is this the case?

And finally, which pumice supplier are people using these days? I've bought from Kaizen Bonsai once or twice and they're very good, but quite expensive, especially when carriage is factored in. I wonder if there's a better way of buying in bulk.

Thanks in advance,
Chris

[MatDz]

[...]
Secondly, I have a bag of the moler clay as used to mop up spills in garages, etc. and I like it, especially for the price, but it's a bit fine for larger plants. I understand that Sanicat is similar but has a larger particle size. Is this the case?
[...]

Exactly, Sanicat/Sophisticat/Kitty friends pink litter is about 5-10 mm, while the Euro Car Part and similar are more in the <5 mm range. I'm not sure about Tesco's litter as I could not find/order it.